I am looking to list all the containers in a pod in a script that gather's logs after running a test. kubectl describe pods -l k8s-app=kube-dns returns a lot of info, but I am just looking for a return like:
etcd
kube2sky
skydns
I don't see a simple way to format the describe output. Is there another command? (and I guess worst case there is always parsing the output of describe).
Answer
kubectl get pods POD_NAME_HERE -o jsonpath='{.spec.containers[*].name}'
Explanation
This gets the JSON object representing the pod. It then uses kubectl's JSONpath to extract the name of each container from the pod.
You can use get and choose one of the supported output template with the --output (-o) flag.
Take jsonpath for example,
kubectl get pods -l k8s-app=kube-dns -o jsonpath={.items[*].spec.containers[*].name} gives you etcd kube2sky skydns.
Other supported output output templates are go-template, go-template-file, jsonpath-file. See http://kubernetes.io/docs/user-guide/jsonpath/ for how to use jsonpath template. See https://golang.org/pkg/text/template/#pkg-overview for how to use go template.
Update: Check this doc for other example commands to list container images: https://kubernetes.io/docs/tasks/access-application-cluster/list-all-running-container-images/
Quick hack to avoid constructing the JSONpath query for a single pod:
$ kubectl logs mypod-123
a container name must be specified for pod mypod-123, choose one of: [etcd kubesky skydns]
I put some ideas together into the following:
Simple line:
kubectl get po -o jsonpath='{range .items[*]}{"pod: "}{.metadata.name}{"\n"}{range .spec.containers[*]}{"\tname: "}{.name}{"\n\timage: "}{.image}{"\n"}{end}'
Split (for readability):
kubectl get po -o jsonpath='
{range .items[*]}
{"pod: "}
{.metadata.name}
{"\n"}{range .spec.containers[*]}
{"\tname: "}
{.name}
{"\n\timage: "}
{.image}
{"\n"}
{end}'
How to list BOTH init and non-init containers for all pods
kubectl get pod -o="custom-columns=NAME:.metadata.name,INIT-CONTAINERS:.spec.initContainers[*].name,CONTAINERS:.spec.containers[*].name"
Output looks like this:
NAME INIT-CONTAINERS CONTAINERS
helm-install-traefik-sjts9 <none> helm
metrics-server-86cbb8457f-dkpqm <none> metrics-server
local-path-provisioner-5ff76fc89d-vjs6l <none> local-path-provisioner
coredns-6488c6fcc6-zp9gv <none> coredns
svclb-traefik-f5wwh <none> lb-port-80,lb-port-443
traefik-6f9cbd9bd4-pcbmz <none> traefik
dc-postgresql-0 init-chmod-data dc-postgresql
backend-5c4bf48d6f-7c8c6 wait-for-db backend
if you want a clear output of which containers are from each Pod
kubectl get po -l k8s-app=kube-dns \
-o=custom-columns=NAME:.metadata.name,CONTAINERS:.spec.containers[*].name
To get the output in the separate lines:
kubectl get pods POD_NAME_HERE -o jsonpath='{range .spec.containers[*]}{.name}{"\n"}{end}'
Output:
base-container
sidecar-0
sidecar-1
sidecar-2
If you use json as output format of kubectl get you get plenty details of a pod. With json processors like jq it is easy to select or filter for certain parts you are interested in.
To list the containers of a pod the jq query looks like this:
kubectl get --all-namespaces --selector k8s-app=kube-dns --output json pods \
| jq --raw-output '.items[].spec.containers[].name'
If you want to see all details regarding one specific container try something like this:
kubectl get --all-namespaces --selector k8s-app=kube-dns --output json pods \
| jq '.items[].spec.containers[] | select(.name=="etcd")'
Use below command:
kubectl get pods -o=custom-columns=PodName:.metadata.name,Containers:.spec.containers[*].name,Image:.spec.containers[*].image
To see verbose information along with configmaps of all containers in a particular pod, use this command:
kubectl describe pod/<pod name> -n <namespace name>
Use below command to see all the information of a particular pod
kubectl get pod <pod name> -n <namespace name> -o yaml
For overall details about the pod try following command to get the container details as well
kubectl describe pod <podname>
I use this to display image versions on the pods.
kubectl get pods -o=jsonpath='{range .items[*]}{"\n"}{.metadata.name}{":\t"}{range .spec.containers[*]}{.image}{end}{end}' && printf '\n'
It's just a small modification of script from here, with adding new line to start next console command on the new line, removed commas at the end of each line and listing only my pods, without service pods (e.g. --all-namespaces option is removed).
There are enough answers here but sometimes you want to see a deployment object pods' containers and initContainers. To do that;
1- Retrieve the deployment name
kubectl get deployment
2- Retrieve containers' names
kubectl get deployment <deployment-name> -o jsonpath='{.spec.template.spec.containers[*].name}'
3- Retrieve initContainers' names
kubectl get deployment <deployment-name> -o jsonpath='{.spec.template.spec.initContainers[*].name}'
Easiest way to know the containers in a pod:
kubectl logs -c -n
Related
We have 3-4 different NetworkPolicy in our Namespace and they are applied based on Pod Selector. Want to know is there any way from Pod side to know which NetworkPolicy is applied on it?
If POD selector used you can use the simple way
kubectl get pod -l \
$( \
kubectl get netpolicies <netpolicy-name> \
-o jsonpath="{.spec.podSelector.matchLabels}"| \
jq -r 'to_entries|map("\(.key)=\(.value)")[]' \
)
This will get the policy selector and use it as input and list the pods
Any way from Pod side
There is no POD side you can check, however I read somewhere kubectl describe pod-name could show Network Policies I tested not showing at least in minikube
So you can use the above command or describe the networkpolicy itself to get POD selector and get an idea.
kubectl describe networkpolicies <name of policy>
The output of kubectl get network policy should display the pod-selector.
After that you can use kubectl get pod -l key=value to list the pods affected.
you can automate this using a bash script/function.
I would also recommend checking "kubectl np-viewer" which is a kubectl plugin, can be found here. This plugin has what you are asking for out of box.
kubectl np-viewer -p pod-name prints network policies rules affecting a specific pod in the current namespace
I have a lot of namespaces and I want to get all pods from a sub-list of namespaces.
For getting all the pods from all namespace the command is:
kubectl get pods --all-namespaces
To get all pods from a spesific namespace the command is:
kubectl get pods -n namespace-name
However I can't find a way to get all pods from a list of namespaces, something like:
kubectl get pods -n namespace-name1, namespace-name2, namespace-name3
what is the right command for that?
kubectl does not support this. You can use egrep to filter the list of all pods by namespaces:
kubectl get pods -A | egrep '^(namespace-name1|namespace-name2|namespace-name3)'
Because kubectl prints the namespace at the beginning of the line, it greps for a line start ^ followed by one of the namespace names.
You can iterate over the subset of namespaces:
Either:
for NAMESPACE in "namespace-1" "namespace-2"
do
kubectl get pods \
--namespace=${NAMESPACE} \
--output=name
done
Or:
NAMESPACE=$(
"namespace-1"
"namespace-2"
)
for NAMESPACE in "${NAMESPACES[#]}"
do
kubectl get pods \
--namespace=${NAMESPACE} \
--output=name
done
This is the output with custom-columns
$ kubectl -n web get pod -ocustom-columns="Name:.metadata.name,Image:.spec.containers[0].image"
Name Image
mysql-0 myrepo.mydomain.com/mysql:5.7
mysql-1 myrepo.mydomain.com/mysql:5.7
mysql-2 myrepo.mydomain.com/mysql:5.7
This is the output with jsonpath for single pod
$ kubectl -n web get pod -o jsonpath="{..metadata.name}:{..spec.containers[0].image}" mysql-0
mysql-0:myrepo.mydomain.com/mysql:5.7
This is the output with jsonpath for multiple pods
$ kubectl -n web get pod -o jsonpath="{..metadata.name}:{..spec.containers[0].image}"
mysql-0 mysql-1 mysql-2:myrepo.mydomain.com/mysql:5.7 myrepo.mydomain.com/mysql:5.7 myrepo.mydomain.com/mysql:5.7
Now how to combine this into a single column or word, something like this, using -ocustom-columns or -ojsonpath
mysql-0=myrepo.mydomain.com/mysql:5.7
mysql-1=myrepo.mydomain.com/mysql:5.7
mysql-2=myrepo.mydomain.com/mysql:5.7
Using kubectl using plain jsonpath:
kubectl get pod -n <namespace> -o jsonpath='{range .items[*]}{.metadata.name}={.spec.containers[*].image}{"\n"}{end}'
Example:
kubectl get pod -n default -o jsonpath='{range .items[*]}{.metadata.name}={.spec.containers[*].image}{"\n"}{end}'
nginx-0=nginx
nginx-1=nginx
nginx-2=nginx
Here range feature is used to loop over all the pods:
{range items[*]} ...<LOGIC HERE>... {end}
Between the range block(As described above), use the jsonpath, notice the = sign is used as per our requirement.
{.metadata.name}={.spec.containers[*].image}{"\n"}
How I can describe the pod information if that is not belongs to default namespace. With default namespace I do not have any issue.
But I wanted to have information for that specific pod which does have namespace align to it.
But when I wanted to describe the same pod I could able to make that, see
I tried with all namespace flag but it does not allow me to query, like this.
kubectl describe pods airflow-scheduler-646ffbfd67-k7dgh --all-namespaces
You would have to explicitly mention the namespace of the pod which you plan to describe. For that, you need to use the -n flag to kubectl command:
kubectl describe pods airflow-scheduler-646ffbfd67-k7dgh -n <namespace>
If you are using bash environment to connect to Kubernetes cluster, you can use the below function to describe the POD from any namespace, you may alias it or put it in your bashrc:
describe_pod()
{
if [ $# -ne 1 ];then
echo "Error: Pod name is missing as input argument"
return 1
fi
pod_name=${1}
kubectl describe pod "${pod_name}" -n $(kubectl get pod -A | awk -v pod="$pod_name" -v def=default '$2==pod{ns=$1} END{if(!length(ns))print def; else print ns}')
}
Example usage:
describe_pod <pod-name-from-any-namespace>
Eg:
describe_pod airflow-scheduler-646ffbfd67-k7dgh
With a simple modification of this function, it can be used for other k8s objects.
I know I can get the pods using:
kubectl get pods -n "namespace", and also to retrieve a json output
I'm trying to expand to get the pods name, the associated images, and a label attribute called 'base'. Also the date when I retrieve this information.
You can try this using yaml output.
kubectl get pods --all-namespaces -o yaml| egrep "name:|image:"
This will give you name of pod and image which is there for running the pod.
OR
kubectl get pods --all-namespaces -o jsonpath="{.items[*].spec.containers[*].image}"
This command will give you all images which are there in all pods.
If you found this is difficult then use,
kubectl get pod --all-namespaces
Check which pods image you need to find then use,
kubectl describe pod <pod_name> -n <namespace>
For reference use Link
Here you can find the description of kubectl get command.
What are you looking for is this:
output o Output format. One of:
json|yaml|wide|name|custom-columns=...|custom-columns-file=...|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=...
See custom columns
[http://kubernetes.io/docs/user-guide/kubectl-overview/#custom-columns],
golang template [http://golang.org/pkg/text/template/#pkg-overview]
and jsonpath template [http://kubernetes.io/docs/user-guide/jsonpath].
For example:
List a pod identified by type and name specified in "pod.yaml" in JSON
output format:
kubectl get -f pod.yaml -o json
Adjust by using the flags that you need from there.
Please let me know if that helped.
You can try jsonpath to retrieve the values for json output.
kubectl get po --all-namespaces -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.containers[0].image}{"\t"}{.metadata.labels.k8s-app}{"\n"}{end}'
probably you can write shell script and achieve this. first try to get all running pods across all namespaces using:
kubectl get pods -all-namespaces
and then iterate over each pod and execute following command:
kubectl describe pods <name of pod>
In the describe command you can get all information that you are looking for.